return self.t doesn't return 0, it returns the function t (which is a property getter). You should distinguish between the attribute and the property getter. Set self._t = 0
– Peter WoodJul 4 '17 at 21:59

1

This question seems to be confused on multiple fronts about the difference between members of a class and members of an instance of a class. For example, temp_con is declared as a class, but in the usage example it appears temp_con is also being used as a variable which is expected to be an instance.
– Daniel PrydenJul 4 '17 at 22:00

answer was a combination of the first 2 answers.
– drako234Jul 4 '17 at 22:12

UPDATE: (memo: read twice)
There's also another problem with your code. First (well, it's second in code, but it will happen first) you define getter t, then later you OVERWRITE it with self.t = 0. As a result you'll get (as t) property accessible as a class member (which happens in your example) and value 0 as object's member.